Aluminum alloys having a pre-determined electrical conductivity

ABSTRACT

An aluminum alloy and a method of making the aluminum alloy comprised of pure aluminum and a casting aluminum. The pure aluminum and casting aluminum are alloyed in appropriate proportions such that the aluminum alloy includes a desired electrical conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) International Annealed Copper Standard (IACS). Embodiments of the aluminum alloy include a combination of A100 aluminum, and A356 aluminum, A357 aluminum, A360 aluminum, and/or A380 aluminum. The aluminum alloy is made for use in applications where an electrical conductivity less than copper is desired (e.g., wiring cables, cast rotors for induction motors, wound rotors for induction motors, and the like).

FIELD OF THE INVENTION

The invention generally relates to metal alloys, and particularly, to aluminum alloys having a pre-determined electrical conductivity.

BACKGROUND

Many electrical applications (e.g., electrical wiring) include copper or copper alloys. Copper and copper alloys are frequently used because their efficient conductive properties are suitable for many applications, and their cost is relatively low. Since copper has such desirable conductive properties, copper is used as the standard by which the conductivity of electrical conductors is measured. As such, conductivity is expressed as a percentage of the International Annealed Copper Standard (IACS), specifically, fifty-eight megasiemens per meter (58 MS/m) or a resistivity (i.e., 1/conductivity) of 1/58 ohm per meter for a copper wire one square millimeter in cross section. Notably, conductivity of one hundred percent (100%) IACS represents a resistivity equal to that of copper.

Some applications, however, do not require the efficiency of copper and/or copper alloys. In fact, if copper and/or copper alloys were used for some of these applications (e.g., some types of induction rotors), too much electricity may be supplied, resulting in corrupted devices and/or circuitry. Therefore, there is a need for alloys which are less efficient conductors of electricity than copper and/or copper alloys.

SUMMARY OF THE INVENTION

As set forth in the detailed description and the figure, the invention includes, in various exemplary embodiments, a castable aluminum alloy. The castable aluminum alloy includes pure aluminum (e.g., A100 aluminum) combined with at least one casting aluminum material (e.g., A356 aluminum, A357 aluminum, A360 aluminum, and/or A380 aluminum), wherein the castable aluminum alloy includes a pre-determined electrical conductivity. The invention also includes a method of making the castable aluminum alloy with an electrical conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) International Annealed Copper Standard (IACS). In addition, the aluminum alloy may be cast to form at least a portion of an induction rotor for an induction motor.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional embodiments of the invention will become evident upon reviewing the non-limiting embodiments described in the specification and the claims, in conjunction with the accompanying figures, wherein:

FIG. 1 is a schematic diagram of an exemplary embodiment of an induction rotor cast of at least a portion of a castable aluminum alloy with a pre-determined conductivity; and

FIG. 2 is a flow diagram of an exemplary embodiment of a method for making a castable aluminum alloy with a pre-determined conductivity.

DETAILED DESCRIPTION

The detailed description of various exemplary embodiments of the invention herein makes reference to the accompanying figures. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical and mechanical changes may be made without departing from the spirit and scope of the invention. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not limited to the order presented.

For the sake of brevity, the apparatus and components of the apparatus may not be described in great detail herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system or method.

Turning now to the figures, FIG. 1 is a schematic diagram of an exemplary embodiment of an induction rotor 100 cast of at least a portion of an aluminum alloy 110. Induction rotor 100 may be any device suitably configured to rotate when a magnetic field created within the device interacts with a magnetic field in an external device. As such, inductor rotor 100 may be any induction rotor known in the art.

Aluminum alloy 110 includes pure aluminum alloyed with a casting aluminum material. In one exemplary embodiment, the pure aluminum is A100 aluminum, which may include approximately 99.7 percent aluminum, although other purity levels considered “pure” in the art are within the scope of the invention. Aluminum alloy 110 may include from about ten percent (10%) to about ninety percent (90%) pure aluminum, by weight, with the remaining proportion being the casting aluminum material, or substantially made up of the casting aluminum material.

The casting aluminum, in various exemplary embodiments, is A356 aluminum, A357 aluminum, A360 aluminum, A380 aluminum, and/or any other type of casting aluminum suitable for use in an induction rotor. As such, aluminum alloy 110 may include from about ten percent (10%) to about ninety percent (90%) casting aluminum, by weight.

By including varying portions of pure aluminum and casting aluminum, the electrical conductivity (i.e., (1/resistivity) as compared to the International Annealed Copper Standard (IACS)) of aluminum alloy 110 can be pre-determined/manipulated depending on a particular/desired application need. The following table includes the approximate IACS resistive values for A100 aluminum, A356 aluminum, A357 aluminum, A360 aluminum, and A380 aluminum. Aluminum Material Approximate IACS Conductivity Value A100 Aluminum 54% A356 Aluminum 40% A357 Aluminum 40% A360 Aluminum 37% A380 Aluminum 27%

As such, aluminum alloy 110 may include conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) IACS. Specifically, aluminum alloy 110 may include conductivity in the range of about forty percent (40%) to about fifty-four percent (54%) IACS when A100 aluminum is alloyed with aluminum A356. Similarly, aluminum alloy 110 may include conductivity in the range of about forty percent (40%) to about fifty-four percent (54%) IACS when A100 aluminum is alloyed with aluminum A357. In addition, aluminum alloy 110 may include conductivity in the range of about thirty-seven percent (37%) to about fifty-four percent (54%) IACS when A100 aluminum is alloyed with aluminum A360. Furthermore, aluminum alloy 110 may include conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) IACS when A100 aluminum is alloyed with aluminum A380. Therefore, for example, if a particular application requires an electrical conductivity of forty-seven percent (47%) IACS, aluminum alloy 110 may include sixty-five percent (65%) A100 aluminum (54% IACS), by weight, and thirty-five percent (35%) A356 aluminum (40% IACS), by weight. Notably, aluminum alloy 110 includes a greater proportion by weight of A100 aluminum as the desired electrical conductivity of aluminum alloy 110 approaches fifty-four percent (54%) IACS. Likewise, aluminum alloy 110 includes a greater proportion by weight of a casting aluminum material as the desired electrical conductivity of aluminum alloy 110 retreats from fifty-four percent (54%) IACS.

In addition, aluminum alloy 110 may also be a combination of A100 aluminum and two or more of A356, A357, A360, and A380 aluminums discussed above to achieve a desired conductivity. Furthermore, two or more of A356, A357, A360, and A380 aluminums discussed above may be alloyed to form aluminum alloy 110 with conductivity in the range of about twenty-seven percent (27%) to about thirty-seven percent (37%) and/or forty percent (40%) IACS.

In one exemplary embodiment, induction rotor 100 includes a body 120, which may be formed of a laminate material. Body 120 may form any suitable shape for rotating within a stator of an induction motor (not shown). Preferably, body 120 forms a cylindrical or substantially cylindrical shape.

Induction rotor 100 also includes end ring 130 and end ring 140 connected to body 120. End rings 130, 140 are each connected to one another via two or more conductor bars 150. In various exemplary embodiments, end rings 130, 140 and/or each conductor bar 150 are formed of aluminum alloy 110. Notably, inductor rotor 100 may include any suitable number of conductor bars 150, as determined by a particular application of induction rotor 100. Moreover, conductor bars 150 may form any suitable size and/or shape for use in induction rotor 100.

In addition, induction rotor 100 includes aperture 160 through body 120. Aperture 160 may form any suitable size and/or shape for use in induction rotor 100. Furthermore, induction rotor 100 includes shaft 170 through aperture 160. Shaft 170 may be any shape and/or size suitable for allowing induction rotor 100 to rotate.

Although the discussion above discloses an induction rotor, aluminum alloy 110 may be used for other appropriate applications where conductivity less than copper is desired. For example, aluminum alloy 110 may be used for wiring cables, cast rotors for induction motors, wound rotors for induction motors, and the like.

FIG. 2 is a flow diagram of an exemplary embodiment of a method 200 for making a castable aluminum alloy (e.g., aluminum alloy 110, discussed above) with a pre-determined conductivity. Method 200, in one embodiment, initiates by alloying pure aluminum and a casting aluminum (step 210). In one embodiment of the invention, pure aluminum is A100 aluminum. In addition, the invention includes any aluminum material considered to be “pure aluminum” in the art.

Method 200 also includes the step of alloying A100 aluminum with one or more of A356 aluminum, A357 aluminum, A360 aluminum, and/or A380 aluminum (step 220). These aluminums are alloyed in appropriate proportions to form an aluminum alloy with a pre-determined conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) IACS (step 230).

In an exemplary embodiment, A100 aluminum is alloyed with A356 aluminum to produce a castable aluminum alloy with an electrical conductivity in the range of about forty percent (40%) to about fifty-four percent (54%) IACS (step 240). In another exemplary embodiment, A100 aluminum is alloyed with A357 aluminum to produce a castable aluminum alloy with an electrical conductivity in the range of about forty percent (40%) to about fifty-four percent (54%) IACS (step 250). In yet another exemplary embodiment, A100 aluminum is alloyed with A360 aluminum to produce a castable aluminum alloy with an electrical conductivity in the range of about thirty-seven percent (37%) to about fifty-four percent (54%) IACS (step 260). In still another exemplary embodiment, A100 aluminum is alloyed with A380 aluminum to produce a castable aluminum alloy with an electrical conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) IACS (step 270). Notably, A356, A357, A360 and/or A380 aluminums may be combined without pure aluminum to produce an aluminum alloy having an electrical conductivity in the range of about twenty-seven percent (27%) to about forty percent (40%) IACS.

Similar to the discussion and examples above, to achieve a pre-determined/desired electrical conductivity, pure aluminum (e.g., A100 aluminum and/or the like) and a casting aluminum (e.g., A356, A357, A360, and/or the like) are alloyed in appropriate proportions based on their individual initial resistive values. For example, if an aluminum alloy with an electrical conductivity of approximately thirty percent (30%) IACS is desired, A380 aluminum (27% IACS) may be alloyed with appropriate proportions of A100 aluminum (54% IACS), and A356 aluminum (40% IACS), A357 aluminum (40% IACS), and/or A360 aluminum (37% IACS). In this example, the proportion of A380 aluminum will be greater than the proportions of A100 aluminum, and A356 aluminum, A357 aluminum, and/or A360 aluminum since the desired electrical conductivity is closer to the initial electrical conductivity of A380 aluminum. In addition, there will be a greater proportion of A380 aluminum in an aluminum alloy comprised of A380 aluminum and A100 aluminum than in an aluminum alloy comprised of A380 aluminum, and A356 aluminum, A357 aluminum, and/or A360 aluminum when the desired conductivity is approximately thirty percent (30%) IACS.

In another example, if an aluminum alloy with an electrical conductivity of approximately fifty percent (50%) IACS is desired, A100 aluminum may be alloyed with appropriate proportions of A356 aluminum, A357 aluminum, A360 aluminum, and/or A380 aluminum. In this example, the proportion of A100 aluminum will be greater than the proportions of A356 aluminum, A357 aluminum, A360, and/or 380 aluminum since the desired electrical conductivity is closer to the initial electrical conductivity of A100 aluminum. In addition, there will be a greater proportion of A100 aluminum in an aluminum alloy comprising A100 aluminum and A380 aluminum than in an aluminum alloy comprising A100 aluminum, and A356 aluminum, A357 aluminum, and/or A360 aluminum when the desired conductivity is approximately fifty percent (50%) IACS.

Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of any or all the claims or the invention. The scope of the invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described exemplary embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. 

1. A castable aluminum alloy, comprising: A100 aluminum alloyed with at least one of A356 aluminum, A357 aluminum, A360 aluminum, and A380 aluminum, wherein the castable aluminum alloy comprises a pre-determined electrical conductivity.
 2. The castable aluminum alloy of claim 1, wherein the castable aluminum alloy is comprised of said A100 aluminum in the range of about ten percent to about 90 percent.
 3. The castable aluminum alloy of claim 2, wherein the castable aluminum alloy is comprised of said at least one of A356 aluminum, A357 aluminum, A360 aluminum, and A380 aluminum in the range of about ten percent (10%) to about ninety percent (90%).
 4. The castable aluminum alloy of claim 3, wherein said pre-determined electrical conductivity is in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) International Annealed Copper Standard (IACS).
 5. The castable aluminum alloy of claim 4, wherein the castable aluminum alloy comprises said A356 aluminum, and said pre-determined electrical conductivity is in the range of about forty percent (40%) to about fifty-four percent (54%) IACS.
 6. The castable aluminum alloy of claim 5, wherein the castable aluminum alloy is comprised of about sixty-five percent (65%) A100 aluminum by weight and about thirty-five percent (35%) A356 aluminum by weight.
 7. The castable aluminum alloy of claim 6, wherein the pre-determined electrical conductivity is about forty-seven percent (47%) IACS.
 8. The castable aluminum alloy of claim 4, wherein the castable aluminum alloy comprises said A357 aluminum, and said pre-determined electrical conductivity is in the range of about forty percent (40%) to about fifty-four percent (54%) IACS.
 9. The castable aluminum alloy of claim 4, wherein the castable aluminum alloy comprises said A360 aluminum, and said pre-determined electrical conductivity is in the range of about thirty-seven percent (37%) to about fifty-four percent (54%) IACS.
 10. The castable aluminum alloy of claim 4, wherein the castable aluminum alloy comprises said A380 aluminum, and said pre-determined electrical conductivity is in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) IACS.
 11. A method of making a castable aluminum alloy with a pre-determined conductivity comprising the steps of: alloying A100 aluminum with at least one casting aluminum to form the castable aluminum alloy, wherein said alloying step comprises the step of alloying said A100 aluminum with said at least one casting aluminum in proportions such that the castable aluminum alloy comprises an electrical conductivity in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) International Annealed Copper Standard (IACS).
 12. The method of claim 11, wherein said alloying step further comprises the step of alloying said A100 aluminum with at least one of A356 aluminum, A357 aluminum, A360 aluminum, and A380 aluminum.
 13. The method of claim 12, wherein said alloying step comprises the step of alloying said A100 aluminum with said A356 aluminum in proportions such that said electrical conductivity is in the range of about forty percent (40%) to about fifty-four percent (54%) IACS.
 14. The method of claim 12, wherein said alloying step comprises the step of alloying said A100 aluminum with said A357 aluminum in proportions such that said electrical conductivity is in the range of about forty percent (40%) to about fifty-four percent (54%) IACS.
 15. The method of claim 12, wherein said alloying step comprises the step of alloying said A100 aluminum with said A360 aluminum in proportions such that said electrical conductivity is in the range of about thirty-seven percent (37%) to about fifty-four percent (54%) IACS.
 16. The method of claim 12, wherein said alloying step comprises the step of alloying said A100 aluminum with said A380 aluminum in proportions such that said electrical conductivity is in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) IACS.
 17. The method of claim 12, wherein said alloying step further comprises the step of alloying said A100 aluminum with each of said A356 aluminum, said A357 aluminum, said A360 aluminum, and said A380 aluminum.
 18. An induction rotor, comprising: a substantially cylindrical body, said body comprising a first side surface and a second side surface; a plurality of conductor bars coupled to said body; and a plurality of end rings coupled to said body; and wherein at least a portion of the induction rotor is comprised of an aluminum alloy with a pre-determined electrical conductivity, said aluminum alloy comprising A100 aluminum and a casting aluminum, wherein said casting aluminum comprises at least one of A356 aluminum, A357 aluminum, A360 aluminum, and A380 aluminum, and wherein said pre-determined electrical conductivity is in the range of about twenty-seven percent (27%) to about fifty-four percent (54%) International Annealed Copper Standard (IACS).
 19. The induction rotor of claim 18, wherein said casting aluminum is A356 aluminum and said pre-determined electrical conductivity is in the range of about forty percent (40%) to about fifty-four percent (54%) IACS.
 20. The induction rotor of claim 19, wherein said aluminum alloy is comprised of about sixty-five percent (65%) A100 aluminum and about thirty-five percent (35%) A356 aluminum, and wherein said pre-determined electrical conductivity is about forty-seven percent (47%) IACS. 